I gave Vera Bradley aprons packed in recipe boxes with a couple of Williams-Sonoma sauces/brines. I have received monogrammed totes, a nice folding picnic blanket and pretty kitchen hand towels in the past.

I would give them something they would actually use and be thrilled about. Although I think the umbrella idea is SUPER cute, it's not always practical for everyone.

Something like a gift certificate is a super easy. Just make sure it has thought put into it. Don't just get them a $50 visa gift card that can be used anywhere, get them a gift card to a well known spa (or one that you know they like.) OR to their favorite resturaunt. If it's in your budget try to make sure that there's enough on the card for 2 visits to where ever you choose.

but if you know they're the type of person to use a tote or umbrella or robe then i'd get them something like that.